rough idle when up to operating temp

[Bluelake]

hey

i have a 07 gmc sierra 1500 for the past year sometimes it will die at idle when warmed up not very often but it does but starts right back up and runs great when driving and towing and never stalls out, just put new plugs about 10,000 ago and doesn’t miss when towing or regular driving so the problem is only at a operating temp idle for about 10 mins it’s fine at top lights but when fully warmed up and idles for about 10 mins fully warmed it will either be rough idle or just stalls but start again immediately

advice

jacob

 

[Bluelake]

I was thinking about cleaning mass airflow sensor maybe engine isn’t getting enough air

 

[Zaedock]

What engine? What mileage? Is the check engine light on? Need more info.

 

[Jetronic]

start looking at fault codes, if any, and live data. fuel trims are important here

 

[BlueOvalFitter]

It very well could be the MAF sensor. Or, the EGR system. IAC, fuel filter, etc. Have you checked for any CEL codes?

 

[zrxkawboy]

That’s the longest sentence I’ve read in a LONG time!

 

[Jetronic]

Did you read it without breathing?

 

[DGXR]

Did you read it without breathing?

I did, and my CPU immediately tripped a fault code

 

[Bluelake]

What engine? What mileage? Is the check engine light on? Need more info.

130,000 and 6.0 and no check engine light

 

[92saturnsl2]

Do you have a scan tool that can read live data? There's cheap ones out there, even a knock-off ELM327 reader would be useful in this situation.

EGR leak or IAC valve are two things that pop in my head right away. But without a code or any other data, we'd just be guessing or you'll be throwing parts at it hoping something sticks.

 

[BlueOvalFitter]

If it were mine, I would start with the basic things. Like, change the fuel filter. Look for any broke, kinked, or disconnected vacuum lines, etc.

 

[Astro14]

Sounds like a vacuum leak…

 

[otis24]

Similar issue. New engine. Runs rough at start up. Replaced coolant temp sensor, swapped out throttle body and EGR with used ones. Was all set to throw in an ECM. Friend scanned it at work; OBD1 scanner. Came up as MAP sensor, which should be the same as MAF in newer vehicles.

 

[92saturnsl2]

Similar issue. New engine. Runs rough at start up. Replaced coolant temp sensor, swapped out throttle body and EGR with used ones. Was all set to throw in an ECM. Friend scanned it at work; OBD1 scanner. Came up as MAP sensor, which should be the same as MAF in newer vehicles.

MAP and MAF are two different sensors regardless of vehicle age.

 

[Escape08]

a clogged up idle control valve?